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demod wip

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This commit is contained in:
jaseg 2020-03-09 13:23:35 +01:00
parent b4d5293d04
commit 9debe084fc
5 changed files with 289 additions and 60 deletions
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23
controller/fw/src/dsss_demod.h
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@ -5,6 +5,9 @@
#define DSSS_GOLD_CODE_COUNT ((1<<DSSS_GOLD_CODE_NBITS) + 1)
#define DSSS_CORRELATION_LENGTH (DSSS_GOLD_CODE_LENGTH * DSSS_DECIMATION)
/* FIXME: move to makefile */
#define DSSS_MATCHER_CACHE_SIZE 8
/* FIXME: move to more appropriate header */
#define PAYLOAD_DATA_BYTE ((PAYLOAD_DATA_BIT+7)/8)
struct iir_biquad {
@ -20,22 +23,26 @@ struct cwt_iir_filter_state {
struct iir_biquad_state st[3];
};
struct {
struct group {
int len; /* length of group in samples */
float max; /* signed value of largest peak in group on any channel */
uint64_t max_ts; /* absolute position of above peak */
int max_ch; /* channel (gold sequence index) of above peak */
} group;
};
struct decoder_state {
int last_phase;
struct matcher_state {
int last_phase; /* 0 .. DSSS_CORRELATION_LENGTH */
int candidate_phase;
float last_score;
float candidate_score;
uint8_t data[PAYLOAD_DATA_BYTE];
#if DSSS_GOLD_CODE_NBITS > 7
#error DSSS_GOLD_CODE_NBITS is too large for matcher_state.data data type (uint8_t)
#endif
uint8_t data[TRANSMISSION_SYMBOLS];
int data_pos;
uint8_t candidate_data;
};
struct dsss_demod_state {
@ -49,9 +56,13 @@ struct dsss_demod_state {
struct group group;
struct group group_cache[DSSS_GROUP_CACHE_SIZE];
struct matcher_state matcher_cache[DSSS_MATCHER_CACHE_SIZE];
};
extern void handle_dsss_received(uint8_t data[TRANSMISSION_SYMBOLS]);
void dsss_demod_init(struct dsss_demod_state *st);
#ifdef SIMULATION
void dsss_demod_step(struct dsss_demod_state *st, float new_value, uint64_t ts, int record_channel);
#else /* SIMULATION */